Laser radar scanning method and laser radar

Abstract

The present invention discloses a laser radar scanning method. The present invention also discloses a laser radar, wherein the laser emitted by each laser emitter passes through a polyhedral prism and a circular structure composed of N galvanometers to form two-dimensional scanning light in the horizontal and vertical directions. The amplitude of the galvanometer is M°, and the three-dimensional scanning light of the M°×360° field of view is formed by combination to realize three-dimensional scanning. The N laser emitters are arranged in a circularly equally divided manner, and the N faces of the corresponding polyhedral prism and the galvanometer on the circular structure are reflected to divide the horizontal 360° field of view into N two-dimensional scanning lights. The scanning time of each vertical angle is increased while maintaining a high horizontal resolution and a scanning refresh rate unchanged, thereby reducing the swing frequency of the galvanometer on the circular structure. The laser radar can realize hybrid solid-state 360° three-dimensional scanning. The invention is used in the field of detection.

Description

Technical Field

[0001] The present invention relates to the field of detection, and in particular to a laser radar scanning method and a laser radar. Background Art

[0002] The laser radars in the existing technology are mainly divided into three categories: mechanical vehicle-mounted laser radars, hybrid solid-state vehicle-mounted laser radars, and all-solid-state vehicle-mounted laser radars.

[0003] The advantages of the first type of mechanical vehicle-mounted lidar are mature technology, superior detection performance, high resolution, and 360° field of view. However, since the resolution in the vertical direction is proportional to the number of laser transmitters and receivers, each transmitter and receiver must be precisely optically aligned, assembled and calibrated during mass production, which results in a large workload, low product yield, and high cost.

[0004] The second type of hybrid solid-state vehicle-mounted laser radar controls the direction of the laser beam to complete the scan by rotating a mirror or a polyhedron prism. The main technology is to use a miniature MEMS scanning mirror to control the direction of the laser beam to complete the scan. The advantage is that the MEMS scanning mirror is relatively mature and can reduce costs. The disadvantage is that it will be affected by vibration, and the deflection angle of the scanning mirror is limited, and the scanning direction is not 360°.

[0005] The third category, all-solid-state LiDAR, is divided into two types: one is the optical phased array (OPA) solution, which uses optical phased array technology to control the laser beam without any moving parts; the other is the flash imaging LiDAR, which does not require beam steering and can illuminate the entire scene with just one flash, and then detects the reflected light through a two-dimensional array image sensor similar to a digital camera. All-solid-state LiDAR does not have any moving parts inside, can be chip-based, and mass production can significantly reduce costs, but the technology is still immature, the ranging distance is short, and it can only scan in one direction. To achieve a 360° field of view, multiple splicing is required.

[0006] Patent CN 107703510 A for the invention of laser radar and laser radar control method discloses a laser radar and a laser radar control method, which uses a vertical galvanometer and a rotating polygonal mirror to complete three-dimensional scanning, and uses a transmitter to realize vertical scanning through the galvanometer, replacing multiple transmitters to reduce costs and structural complexity. However, since unmanned driving requires the laser radar to have a horizontal resolution of 0.1° and a refresh rate of 10 frames or more, and the measurement distance must reach 200m, according to this technical requirement, the time for each 0.1° scan in the horizontal direction is 27μs, and each measurement time is at least 2μs. Only 13 measurements can be made in the vertical direction, that is, the vertical resolution can only be 2.2°, so it does not meet the technical parameter requirements of the first type of multi-transmitter / receiver laser radar and cannot be completely replaced. Summary of the invention

[0007] The object of the present invention is to provide a hybrid solid-state laser radar scanning method.

[0008] The invention also provides a laser radar.

[0009] The technical solution adopted by the present invention is:

[0010] According to the laser radar scanning method of the first aspect of the present invention, the method comprises: controlling N laser emitters arranged in equal parts of a circle to emit lasers to a polyhedral prism corresponding to N faces, and forming N synchronous scanning lights with a scanning angle of 360° / N after reflection by the polyhedral prism, and emitting the scanning lights to a circular structure composed of N galvanometers, the amplitude of which is M / 2°, to form N two-dimensional scanning lights with a 360 / N°XM° field of view on a horizontal 360° field of view, and after being combined, forming a three-dimensional scanning light with a M°X 360° field of view on a horizontal 360° field of view, thereby realizing a 360° three-dimensional scanning.

[0011] This laser radar scanning method forms two-dimensional scanning light in the horizontal and vertical directions through the laser emitted by each laser emitter passing through a polyhedral prism and a circular structure composed of N galvanometers. The amplitude of the galvanometer is M / 2°, and three-dimensional scanning light with a field of view of M°×360° is formed after combination to achieve three-dimensional scanning. N laser emitters are arranged in a circularly equally divided manner, corresponding to the N faces of the polyhedral prism and the galvanometer on the circular structure for reflection, and the horizontal direction is divided into N two-dimensional scanning lights. The scanning time of each vertical angle is increased while maintaining a high horizontal resolution and a scanning refresh rate, thereby reducing the swing frequency of the galvanometer on the circular structure.

[0012] A laser radar according to an embodiment of the second aspect of the present invention comprises:

[0013] at least two laser emitters for reflecting the detection laser, the number of the laser emitters being N;

[0014] A polyhedron prism, wherein the polyhedron prism has N faces and is rotatable, and is used to refract a point light source to form a scanning light with a scanning angle of 360° / N;

[0015] A circular structure, wherein the circular structure is composed of N galvanometer mirrors, the amplitude of the galvanometer mirrors is M / 2°, and each of the galvanometer mirrors is vibrated and reflected to convert the scanning light of the polyhedron prism into N two-dimensional scanning lights with M°×360° / N fields of view;

[0016] The motor control module includes a first motor control module and a second motor control module. The first motor control module drives the polyhedral prism to rotate, and the second motor control module drives the N galvanometers of the circular structure to swing synchronously.

[0017] This laser radar includes N laser emitters, a polyhedral prism, a circular structure composed of N galvanometers, and a motor control module. The lasers emitted by each laser emitter pass through the rotating polyhedral prism and the galvanometer of the circular structure to form N 360 / N°XM° two-dimensional scanning lights in a 360° field of view, thereby realizing hybrid solid-state 360° three-dimensional scanning.

[0018] As a further improvement of the technical solution of the present invention, the laser emitters are arranged in a circularly equally divided manner.

[0019] As a further improvement of the technical solution of the present invention, the N faces of the polyhedral prism are arranged in a circularly equally divided manner and correspond to N laser emitters.

[0020] As a further improvement of the technical solution of the present invention, the polygonal prism is a reflective polygonal prism or a refracting polygonal prism.

[0021] As a further improvement of the technical solution of the present invention, the N oscillating mirrors on the circular structure are arranged in a circular manner and correspond to the N faces of the polyhedral prism and oscillate synchronously with the same amplitude.

[0022] As a further improvement of the technical solution of the present invention, both the No. 1 motor control module and the No. 2 motor control module are equipped with a code disk for determining the emission angle of the laser in the horizontal and vertical directions.

[0023] As a further improvement of the technical solution of the present invention, it also includes receivers of the same number as the laser transmitters, and the receivers are installed in a housing at equal intervals.

[0024] As a further improvement of the technical solution of the present invention, it also includes a focusing unit, which is arranged before the receiver and focuses the reflected laser to the receiver.

[0025] As a further improvement of the technical solution of the present invention, it also includes a collimating unit, which is arranged between the laser emitter and the polygonal prism, and is used to collimate the outgoing laser emitted by the laser emitter. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below in conjunction with the accompanying drawings:

[0027] Figure 1 This is a schematic diagram of an optical path system according to Embodiment 1 of the present invention;

[0028] Figure 2 A top view of the laser radar of Example 1 of the present invention;

[0029] Figure 3 This is a front view of the laser radar of Example 1 of the present invention;

[0030] Figure 4 This is a schematic diagram of an optical path system according to Embodiment 2 of the present invention;

[0031] Figure 5 A top view of a laser radar according to Embodiment 2 of the present invention;

[0032] Figure 6 This is the front view of the laser radar of Example 2 of the present invention. DETAILED DESCRIPTION

[0033] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0034] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0035] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0036] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0037] A laser radar scanning method is provided, wherein N laser emitters 100 arranged in equal parts according to a circle are controlled to emit lasers to a polyhedral prism corresponding to N faces, and N synchronous scanning lights with a scanning angle of 360° / N are formed after reflection or refraction by the polyhedral prism. The scanning lights are emitted to a circular structure composed of N galvanometers (with an amplitude of M / 2°) to form N two-dimensional scanning lights with a 360° / N°×M° field of view on a horizontal 360° field of view, and after being combined, three-dimensional scanning lights with a M°×360° field of view on a horizontal 360° field of view are formed, thereby realizing 360° three-dimensional scanning.

[0038] A laser radar includes at least two laser emitters 100 for reflecting detection lasers, a polyhedral prism, a circular structure 300, and a motor control module 400. The number of laser emitters 100 is N, the polyhedral prism has N faces, the polyhedral prism can be rotatably arranged, the polyhedral prism is used to reflect or refract a point light source to form a scanning light with a scanning angle of 360° / N, the circular structure 300 is composed of N galvanometers (M / 2° amplitude), and the scanning light after passing through the polyhedral prism is transformed into a two-dimensional scanning light of N 360 / N°XM° fields of view on a horizontal 360° field of view through vibration reflection of each galvanometer, and the motor control module 400 includes a first motor control module 410 and a second motor control module 420, the first motor control module 410 drives the polyhedral prism to rotate, and the second motor control module 420 drives the N galvanometers of the circular structure 300 to swing synchronously with an amplitude of M / 2°.

[0039] Furthermore, the laser emitters 100 are arranged in a circularly equally divided manner. The N faces of the polyhedral prism are arranged in a circularly equally divided manner and correspond to the N laser emitters 100. The N galvanometers on the circular structure 300 are arranged in a circular manner and correspond to the N faces of the polyhedral prism and oscillate synchronously with the same amplitude.

[0040] Reference Figure 1-Figure 3 According to the laser radar of Example 1, it includes 20 laser emitters 100 in each upper and lower layers, a rotating reflective polyhedron prism 210 composed of 40 reflective surfaces, a circular structure 300 composed of 20 mechanical galvanometers on the upper and lower surfaces, a motor control module 400, and a receiver 600. Among them, the 40 laser emitters 100 simultaneously emit detection lasers, which are reflected by the rotating rotating reflective polyhedron prism 210 to form two layers of 20 synchronous, 18° scanning angle ring scanning lights, and then pass through the 20 mechanical galvanometers (9° amplitude in the vertical direction) on the circular structure 300 to form two layers of 20 18°×18° field of view two-dimensional scanning lights, forming 36°×360° three-dimensional scanning lights, realizing hybrid solid-state 360° three-dimensional scanning.

[0041] Reference Figure 4-Figure 6According to the laser radar of Example 2, it includes 20 laser emitters 100 in each upper and lower layers, a rotating refractive polyhedron prism 220 composed of 40 refractive surfaces, a circular structure 300 composed of 20 mechanical galvanometers on the upper and lower surfaces, a motor control module 400 and a receiver 600. The 40 laser emitters 100 simultaneously emit detection lasers, which form two layers of 20 synchronous scanning lights with a scanning angle of 18° after passing through the rotating refractive polyhedron prism 220, and then form two layers of 20 two-dimensional scanning lights with a field of view of 18°×18° after passing through the 20 galvanometers (9° amplitude) on the circular structure, which are combined into 36°×360° three-dimensional scanning lights to achieve hybrid solid-state 360° three-dimensional scanning.

[0042] In Example 1 and Example 2, 40 laser emitters 100 are arranged in two layers in a circularly equally divided manner, corresponding to each face of the polyhedral prism and the galvanometer on the circular structure 300 for reflection, and the 360° field of view is divided into two layers of 20 18°×18° two-dimensional scanning lights, which greatly increases the scanning time of each vertical angle while maintaining a high horizontal resolution and a scanning refresh rate, thereby improving the vertical resolution and reducing the swing frequency of the galvanometer on the circular structure 300, so that the motor speed of the No. 2 motor control module 420 on the circular structure 300 that controls the swing of the galvanometer will not exceed the maximum speed of the existing motor and become unusable. At the same time, in this embodiment, a circular structure 300 composed of 20 mechanical galvanometers is used to control the synchronous swing of 20 mechanical galvanometers on the upper and lower surfaces through the rotation of a motor, thereby replacing 40 MEMS galvanometers, thereby greatly reducing costs.

[0043] It can be understood that both the first motor control module 410 and the second motor control module 420 are equipped with a code disk 500 for determining the emission angle of the laser in the horizontal and vertical directions.

[0044] In a specific embodiment, a receiver 600 is also provided. The number of the receivers 600 is equal to that of the laser transmitter 100. The receivers 600 are installed in a housing at equal intervals. The receivers 600 may adopt an APD or SIPM sensor. In order to better receive the signal. A focusing unit is provided before the receiver 600. The focusing unit focuses the reflected laser to the receiver 600. A collimating unit is provided between the laser transmitter 100 and the polyhedral prism. The collimating unit is used to collimate the outgoing laser emitted by the laser transmitter 100.

[0045] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in the technical field without departing from the purpose of the present invention.

Claims

1. A laser radar scanning method, characterized in that: include: Controlling N laser emitters arranged in equal parts of a circle to emit lasers to the corresponding N faces of a polyhedral prism, and forming N synchronized scanning lights with a scanning angle of 360° / N after reflection or refraction by the polyhedral prism, and emitting the scanning lights to a circular structure composed of N galvanometers, the amplitude of which is M / 2°, to form N two-dimensional scanning lights with a field of view of 360 / N°XM° on a horizontal 360° field of view, and after being combined, forming a three-dimensional scanning light with a field of view of M°X 360° on a horizontal 360° field of view, thereby realizing a 360° three-dimensional scanning; The circular structure is composed of a mechanical galvanometer; The N faces of the polyhedral prism are arranged in a circularly equally divided manner and correspond to N laser emitters; The N oscillating mirrors on the circular structure are arranged in a circular manner and correspond to the N faces of the polyhedral prism and oscillate synchronously with the same amplitude.

2. A laser radar, characterized in that: include: at least two laser emitters for reflecting the detection laser, the number of the laser emitters being N; A polyhedral prism, wherein the polyhedral prism has N faces and is rotatable, and is used to reflect or refract a point light source to form a scanning light with a scanning angle of 360° / N; A circular structure, wherein the circular structure is composed of N galvanometer mirrors, each of which has an amplitude of M / 2°, and each of which, through vibration reflection, converts the scanning light of the polyhedron prism into two-dimensional scanning light of N horizontal 360 / N°× vertical M° fields of view in a horizontal 360° field of view; A motor control module, wherein the motor control module comprises a first motor control module and a second motor control module, wherein the first motor control module drives the polyhedral prism to rotate, and the second motor control module drives the N galvanometers of the circular structure to swing synchronously; The circular structure is composed of a mechanical galvanometer; The laser emitters are arranged in a circularly equally divided manner; The N faces of the polyhedral prism are arranged in a circularly equally divided manner and correspond to N laser emitters; The N oscillating mirrors on the circular structure are arranged in a circular manner and correspond to the N faces of the polyhedral prism and oscillate synchronously with the same amplitude.

3. The laser radar according to claim 2, characterized in that: The polygonal prism is a reflective polygonal prism or a refracting polygonal prism.

4. The laser radar according to claim 2, characterized in that: The first motor control module and the second motor control module are both equipped with code disks for determining the emission angles of the laser in the horizontal and vertical directions.

5. The laser radar according to claim 2, characterized in that: It also includes receivers of the same number as the laser transmitters, and the receivers are installed in a shell at equal intervals.

6. The laser radar according to claim 5, characterized in that: The device also includes a focusing unit, which is arranged before the receiver and focuses the reflected laser light onto the receiver.

7. The laser radar according to claim 2, characterized in that: It also includes a collimating unit, which is arranged between the laser emitter and the polygonal prism, and is used to collimate the outgoing laser emitted by the laser emitter.

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